In the interest in replacing ammonium perfluorooctanoate as the stabilizing surfactant in the polymerization of certain fluoromonomers, notably VF2, recent patents disclose the use of hydrocarbon surfactants for this purpose. For example, U.S. Pat. No. 7,122,610 (Wille et al.) demonstrates the use of certain alkane-sulfonates, sulfones, and disulfones in the polymerization to form non-elastomeric fluoropolymers containing at least 71 wt % vinylidene fluoride (VF2). Such polymers are known to be low melting, i.e. polyvinylidene fluoride (PVDF) has a melting temperature of 155-192° C. (p. 27 of S. Ebnesajjad, Fluoroplastics, Vol. 2 melt Processible Fluoropolymers, Plastics Design Library (2003)). U.S. Pat. No. 7,521,513 (Tang) demonstrates the use of sodium octyl sulfonate in the polymerization to form VF2/HFP fluoroelastomer, wherein the low molecular weight of the fluoroelastomer is indicated by its inherent viscosity being determined by the Mooney Viscometer method, wherein the fluoroelastomer is flowable at 121° C. so that its resistance to shear can be measured at this temperature. U.S. Pat. No. 3,391,099 (Punderson) demonstrates in Example VI the use of sodium lauryl sulfate in the polymerization of TFE and a small amount of HFP to form a sinterable modified PTFE. Example VI also uses 260 ppm of fluorinated surfactant, AFC (ammonium ω-hydrohexadecafluoronanoate), so this polymerization is not fluorosurfactant-free.
There is a need for greatly reducing or entirely eliminating fluorosurfactant in the aqueous dispersion polymerization of fluoromonomer to form fluoropolymers, e.g. the non-melt-processible perfluoroplastics such as, polytetrafluoroethylene (PTFE) and the melt-fabricable perfluoroplastics such as tetrafluoroethylene/hexafluoropropylene copolymer (FEP) and tetrafluoroethylene/perfluoro(alkyl vinyl ether) (PFA).